The above Agnostid (not Agnostic, that's me, and a much bigger fossil.) is only 8mm long. It has had a troubled past, being quite unsure if it is a trilobite or a mere, less distinguished (if I understand correctly), mandibulate crustacean (i.e like lobsters, crabs and shrimps). If anyone wants to pursue this further, I suggest you start with, Burgess Shale fossils shed light on the agnostid problem. (2019). I dare not go there myself, as the words are too big, and too many.